Time restricted eating – a beginner's guide

In modern life we are surrounded by food, all of the time. It is available 24 hours a day, seven days a week, ready in an instant at any time of the day or night for when we feel a bit peckish. We have become a society of grazers. For the vast majority of us, we know exactly where our next meal is coming from and we are in little danger of going hungry any time soon.

So what if this was part of our problem? Exciting new research shows that eating within a restricted time zone each day could be the answer to our battle of the bulge, not to mention the effects of restricted eating on our risk of heart disease, type 2 diabetes, high cholesterol and other chronic diseases of our time.

24-hour body clock

Thanks to the BBC’s Dr Michael Mosley, most of us have heard of intermittent fasting – the 5:2 and 16:8 diets are popular versions of this way of eating but now scientists believe that our internal body clock, also known as our circadian rhythm, has a bigger role to play in our health than we realise. This theory is called Time Restricted Feeding (or TRF).

This 24-hour body clock is regulated and controlled by light, so when we wake to natural daylight, melatonin, our sleep hormone is suppressed and cortisol levels start to increase, to energise us and kick-start our morning. This daily cycle allows us to repair and regenerate when we are at rest, and triggers bodily functions like digestion for times when we are awake and alert. Restricting our eating to certain hours a day mimics our evolution and works with the body’s biochemistry to bring some balance back to the body.

A natural time to fast

The theory is that if we can fast for a few hours each day, we give our body a chance to repair. This seems especially effective if our fasting zone is in the evening, for a few hours before we go to bed, to align with our natural circadian rhythm.

People have reported improved energy levels, better and more refreshing sleep and weight loss as being among some of the benefits of intermittent fasting.

The great thing about this ongoing research is that it seems that simply abstaining from food for anything between eight and 12 hours each day is enough to reap the benefits.

How to get started

If you are new to this idea of time-restricted eating, start off eating within a 12-hour window – eg if you eat breakfast at 8am, then finish your day’s eating by 8pm. If you want to take it a step further, increase the fasting time to 14 or 16 hours, so you eat within a 10 or eight-hour window (eg 8am to 6pm, or 8am to 4pm). It is OK to drink tea, coffee, herbal teas or water outside this time, but refrain from alcohol, fruit juice or soft drinks in the fasting window.

Most diets tell us what to eat. Instead, this way of eating focusses on when to eat. Of course, it is still important to make sure you are eating a well-balanced and nutritious diet.

Here’s an example of what a typical day’s diet might look like if we were to eat within a 10-hour window:

:: Breakfast around 8am: low-sugar granola with natural yoghurt and berries.

:: Snack 10am – an apple and a handful of nuts

:: Lunch – around 1pm: chicken salad with tomatoes, salad leaves, grated carrot, peppers, olives, olive oil and balsamic dressing with a few oatcakes and houmous.

:: Afternoon snack – a banana

:: Dinner – by 6pm: Fish with steamed veg and baby boiled new potatoes.

In the evening have some herbal tea or water.

This blog first appeared as an article in The Irish News on Saturday 23 June 2018.